This invention relates generally to toggle wrenches that are operated by pressing a hand lever toward the handle and more particularly to such a toggle wrench having parallel jaws disposed at an angle of generally thirty degrees relative to the handle thereof.
In this field, wrenches mass produced have had jaws that approach a nut or bolt while being at an angle to each other. This is damaging to the nuts and bolts of good machinery.
The main object of this invention is to provide such a wrench with jaw surfaces which move in parallelism toward a nut for engaging the flat sides of the nut over broad areas.
Parallel jaw adjustable wrenches of the past have operated by the manipulation of worm gears. Such wrenches have a looseness and tend to slip off of a nut while great wrenching pressure is being applied. The suddenly released pressure causes an operator's knuckles to fly through the air, often being bodily cut on adjacent machinery and so they are nick-named "knuckle-busters".
The advantages of parallel jaws combined with the high gripping of a toggle are provided by the wrench hereof.
An earlier model, described in U.S. patent application titled PARALLEL JAW TOGGLE WRENCH WITH HOUSING, Ser. No. 07/232,591 and filed Aug. 15, 1988, the inventor being Donald J. Finn, shows a wrench having the advantages hereof with the exception that an angle of parallel jaw surfaces to handle length of substantially 30 degrees was not attainable therewith.
A hexagonal nut has tow surfaces at each corner that lie in planes 120 degrees apart and it is for that reason that the 30 degree handle angle is more effective.
Many nuts are in such tight spots that a 60 degree wrenching stroke is not possible. It is then that an approximately 30 degree angled-handle is most desirable.
This angle of approximately 30.degree. permits the wrench hereof to be used in a very tight spot in the manner of most end wrenches. This advantage was not possible with the wrench of my own earlier application because a line between the my own earlier application because a line between the hand lever pivot and the sliding jaw would have been too near to a 90 degree angle.
This problem has been solved by experiment and with concepts in the wrench hereof (a) by providing a link between the hand lever and the sliding jaw, and (b) by providing for the pivot connection between the hand lever and the link to move upwardly, not downwardly, as the hand lever is squeezed toward the desirable 30 degrees even in a workable parallel jaw toggle wrench.
The prior art has a wrench in U.S. Pat. No. 4,274,312 issued Jun. 23, 1981 to Kenneth F. Finn and titled: PARALLEL JAW TOGGLE WRENCH. It has never been marketed. It lacked the strength needed to prevent bending of parts.
The wrench hereof is distinguished by being very rigid, very strong, and without any bending, or "give" or, "springing". This is because it's special open-topped housing of U-shape forms what can be termed "THE IRON TRIANGLE" as explained herein.